Reovirus is a member of a large family of double-stranded RNA viruses which all present a facinating problem in chromosome organization. The problem is how each virus particle receives a complete set of the 10 pieces of double-stranded RNA that are extracted with phenol. An RNA-protein complex containing all of the reovirus RNA in one circle is extracted by 4 M guanidine hydrochloride and the protease inhibitor phenylmethylsulfonyl fluoride (PMSF). The absolute requirement for PMSF suggests that protein may link the pieces of RNA together. This possibility will be examined by electron microscopy and gel electrophoresis. If a protein linkage is found, it will be characterized; and the protein will be identified biochemically and mapped electron-microscopically. The electron microscope also will be used to map the sequences of pieces in individual complexes to determine whether the order of pieces is random or unique, and whether the genes are continguous.